Unitized flatbed trailer structure and container truck floor structure

ABSTRACT

A flatbed trailer design that unitizes the three main components of a trailer bed, the main rails, the cross members and the floor, to create a lightweight and stronger trailer. The trailer design comprises two main rails having dual webs and a plurality of shouldered cross members. These dual web main rails and shouldered cross members have top flanges that are formed by the upper plane of the flooring members. In addition, intermediate flooring supports are used between cross members. A flooring/cross member design for box-type (e.g., van) trailers, box-type bodies or even container bodies, whose top flanges of the cross members are formed by the upper plane of the flooring and whose flooring supports are intermediate, exhibiting a combined lower height. This result provides more interior space for these type of trailers while maintaining, or even reducing, the size of the cross member. This unitized flooring also forms the lower flange of the box or chassis, thereby increasing the strength of the box itself.

FIELD OF THE INVENTION

The invention pertains to flatbed trailers and box-type truck structures(e.g., vans, container chassis, etc.). In particular, the inventionpertains to an improved flatbed trailer design, as well as an improvedvan design.

BACKGROUND OF INVENTION

The main bearing members for loads placed on flatbed trailers are thepair of I-beams, generally known as the "main beams" which runlongitudinally the length of the bed. Properly fabricated, the beams areflexed or curved vertically upward and designed to compress orstraighten longitudinally under load. Floor supports in the form of amultiplicity of "C" channel, or "I-beam", cross members are bolted orwelded perpendicularly to the webs of the main beams and directedoutboard to define the width of the bed. Disposed on top of the crossmembers are floor sections, typically welded to each otherlongitudinally or butted against each other snugly and held in positionby guide structures and floor screws.

Two basic problems occur in these constructions. Welding of the crossmembers and floor sections to the main beam reduces its load bearingstrength most particularly if it is heat-treated aluminum and thereforerequires a sacrifice in load capacity by as much as 20%. In the buttedfloor section construction, since the floor sections are essentiallyloose, they serve very little load bearing function and do not compresswith the main beam. What they do is transmit the load to the underlyingcross member which, in turn, transmits the load to the main beam.Furthermore, the typically preferred use of aluminum in flatbed trailerconstruction to increase load capacity is particularly defeated byextensive welding and loose floor sections tend to minimize payload.

The following U.S. patents are related to the field of truckconstruction.

Various types of truck body construction are disclosed in U.S. Pat. Nos.1,962,497 (Francis); 2,818,272 (DeLay); 3,003,810 (Kloote et al.);3,096,996 (Cole); 3,163,434 (Krueger); 3,393,920 (Ehrlich); 3,692,349(Ehrlich); 3,843,156 (Alfriend, Jr. et al.); 4,221,427 (Sentle, Jr. etal.); 4,232,884 (DeWitt); 4,671,562 (Broadbent); 4,787,669 (Wante);4,906,021 (Rowe et al.); 5,085,025 (Gaddis); 5,188,418 (Walworth, Jr. etal.); 5,205,587 (Orr); 5,401,050 (Baker); 5,417,453 (VanDenberg);5,474,331 (Booher); 5,558,369 (Cornea et al.); and 5,655,792 (Booher).

Various floor constructions for trucks are disclosed in U.S. Pat. Nos.2,485,047 (Greig); 2,773,718 (Bohlen); 4,656,809 (Wilson); 4,951,992(Hockney); 5,054,843 (Gray).

Conventional prior art truck bed designs are depicted in FIGS. 1-3. Inparticular, FIG. 3 shows the typical two main rail "I-beam" 10 designwhereby the main rails 10 run the length of the truck bed and aredesigned for supporting the payload. Each I-beam 10 comprises an upperflange 11, a lower flange 13 and a web 15. Cross members 12 aretransversely coupled between the main rails 10 through the webs 15. Itshould be understood that U-shaped cross members 12 are depicted forexample only; other conventional types of cross members could have beendepicted such as I-beam, c-channel or circular cross-sectioned crossmembers. Flooring members 14 are then disposed in between the main rails10 on top of the cross members 12; these flooring members 14 may havefeet 16 (FIGS. 1 and 3) or even a bottom surface 18 (FIG. 2) that reston top of the cross members 12. These feet 16 or bottom surface 18 canthen be fastened to the cross members 12 by bolting or welding (notshown). In these instances, the top surface 20 of the flooring member14, where the payload is eventually positioned, is thus set off from thetop surface 22 of the cross member 12.

However, in such a design the three main components, i.e., the mainrails 10, the cross members 12 and the flooring member 14, all workindependently of each other. Such a design does not efficiently transferthe load from the payload into the main rails 10. When the payload ispositioned on the flooring members 14 for transport, the weight istransferred through the top surface 20 of the flooring member 14,through the feet 16 and bottom surface 18 (if present), through thecross members 12 and eventually to the main rails 10. Incontradistinction, the optimum design would have the payload restingdirectly on the main rails 10, i.e., unitizing of the top surface of theflooring member 14 with the top surface of the cross members 12 and themain rails 10.

Thus, there remains a need for a lightweight, integrated flatbed designthat effectively makes the top surface of the floor the top surface ofthe main rails and the top surface of the cross members, therebyallowing the direct transfer of load from the payload to the main rails.

OBJECTS OF THE INVENTION

Accordingly, it is the general object of this invention to overcome thedisadvantages of the prior art.

It is an object of the present invention to provide a flatbed trailerdesign having main rails, cross members and flooring members that actdependently on each other.

It is still yet another object of the present invention to provide aflatbed trailer design having flooring members that operate as the topflange of the main rails, thereby increasing the strength of the mainrails.

It is still yet another object of the present invention to provide aflatbed trailer design having flooring members that operate as the topflange of the cross members.

It is an object of the present invention to provide a flatbed trailerdesign that unitizes the upper surface of the floor with the top surfaceof the main rails, thereby optimizing the strength of the main rail.

It is another object of the present invention to increase the number ofmain rail support points for the cross members.

It is another object of the present invention to reduce the unsupportedlength of the cross members, thereby reducing the size of the crossmembers.

It is another object of the present invention to provide a flatbedtrailer design that unitizes the upper surface of the floor with the topsurface of the cross member, thereby optimizing the strength of thecross members.

It is even yet another object of the present invention to reduce thenumber of lower cross members in a flatbed trailer, thereby furtherreducing the weight of the trailer.

It is another object of the present invention to provide a van or boxtrailer or container design that presents more storage room by loweringthe floor height while maintaining the necessary payload support.

It is still another object of the present invention to reduce the numberof cross members required in a van, box trailer or container design butstill retain the same unsupported length of the flooring member betweenthe cross members.

It is even yet a further object of the present invention to reduce theweight and assembly time of the van, box trailer or container design byreducing the number of cross members.

It is yet another object of the present invention to provide a van orbox trailer or container design that presents more storage room bylowering the floor height while maintaining the same size cross member.

It is still yet another object of the present invention to provide a vanor box trailer or container design that presents more storage room bylowering the floor height while reducing the size of the cross member.

It is still yet another object of the present invention to provide a vanor box trailer or container design that is strengthened while loweringthe floor height.

It is another object of the present invention to increase the payloadcarrying capacity while reducing the weight of the truck or van, boxtrailer or container design.

SUMMARY OF THE INVENTION

These and other objects of the instant invention are achieved byproviding a vehicle (e.g., a flatbed trailer) having a longitudinal axisand comprising: at least two main rails oriented parallel to thelongitudinal axis of the vehicle, a plurality of cross members orientedtransversely of the longitudinal axis and through the at least two mainrails, and flooring members assembled the said cross members and withthe at least two main rails that form an upper flange of the at leasttwo main rails.

These and other objects of the instant invention are also achieved byproviding a vehicle (e.g., a flatbed trailer) having a longitudinal axisand comprising: at least two main rails oriented parallel to thelongitudinal axis of the vehicle, a plurality of cross members orientedtransversely of the longitudinal axis and through the at least two mainrails, and flooring members assembled with the cross members and withthe at least two main rails that form an upper flange of each of theplurality of cross members.

These and other objects of the instant invention are also achieved byproviding a vehicle (e.g., a flatbed trailer) having a longitudinal axisand comprising: at least two main rails oriented parallel to thelongitudinal axis of the vehicle, a plurality of cross members orientedtransversely of the longitudinal axis and through the at least two mainrails, and flooring members assembled with the cross members and withthe at least two main rails, thereby forming an upper flange of the atleast two main rails and an upper flange of each of the plurality ofcross members.

These and other objects of the instant invention are also achieved byproviding a vehicle (e.g., a flatbed trailer) having a longitudinal axisand comprising: at least two main rails oriented parallel to thelongitudinal axis of the vehicle, a plurality of cross members orientedtransversely of the longitudinal axis and through the at least two mainrails, and intermediate flooring support members disposed in between theplurality of cross members for supporting flooring members thereon.

These and other objects of the instant invention are also achieved byproviding a vehicle (e.g., a flatbed trailer) having a longitudinal axisand comprising: at least two main rails oriented parallel to thelongitudinal axis of the vehicle and each of the at least two main railscomprising a plurality of webs; a plurality of cross members orientedtransversely of the longitudinal axis and through the at least two mainrails; and the plurality of webs providing more than two points ofsupport for each one of the plurality of cross members, thereby reducingthe unsupported length of each one of the plurality of cross members.

These and other objects of the instant invention are also achieved byproviding a vehicle (e.g., a flatbed trailer) having a longitudinal axisand comprising: at least two main rails oriented parallel to thelongitudinal axis of the vehicle; a plurality of cross members orientedtransversely of the longitudinal axis and through the at least two mainrails; and wherein each of the cross members comprises shoulders forsupporting intermediate flooring support members thereon to supportflooring members in between the cross members.

These and other objects of the instant invention are also achieved byproviding a vehicle having a box-type structure (e.g., vans,refrigerated vans, container chassis, etc., that only utilize crossmembers with no main rails) and having a longitudinal axis, whereby thevehicle comprises: a plurality of cross members oriented transversely ofthe longitudinal axis; and flooring members assembled with the pluralityof cross members to form an upper flange of each of the plurality ofcross members.

These and other objects of the instant invention are also achieved byproviding a vehicle having a box-type structure (e.g., vans,refrigerated vans, container chassis, etc., that only utilize crossmembers with no main rails) and having a longitudinal axis, whereby thevehicle comprises a plurality of cross members oriented transversely ofthe longitudinal axis; and intermediate flooring support membersdisposed in between the plurality of cross members for supportingflooring members thereon.

These and other objects of the instant invention are also achieved byproviding a vehicle having a box-type structure (e.g., vans,refrigerated vans, container chassis, etc., that only utilize crossmembers with no main rails) and a longitudinal axis and wherein thevehicle includes a roof that acts as a top flange to the box-typestructure and comprises: a plurality of cross members orientedtransversely of the longitudinal axis; and flooring members assembledwith the plurality of cross members to act as a lower flange to thebox-type structure.

These and other objects of the instant invention are also achieved byproviding a vehicle having a box-type structure (e.g., vans,refrigerated vans, container chassis, etc., that only utilize crossmembers with no main rails) and a longitudinal axis and wherein thevehicle includes a roof that acts as a top flange to the box-typestructure and comprises: a plurality of cross members orientedtransversely of the longitudinal axis; and wherein each of the crossmembers comprises shoulders for supporting intermediate flooring supportmembers thereon to support flooring members in between the crossmembers.

DESCRIPTION OF THE DRAWINGS

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

FIG. 1 is a partial, cross-sectional view of a prior art truck beddesign showing one main rail "I-beam", a portion of a cross member and aportion of a flooring member resting thereon;

FIG. 2 is a partial cross-sectional view of a prior art truck bed designshowing a portion of the cross member and alternative flooring memberresting thereon;

FIG. 3 is a partial isometric view of a prior art truck bed designshowing a portion of two main rail I-beams, a portion of two crossmembers, and a portion of a flooring element resting on the crossmembers;

FIG. 4 is an isometric view, shown in cut-a-away, depicting theintegrated truck bed structure of the present invention;

FIG. 5 is an enlarged isometric view, shown in cut-a-away, depicting thedual web main rails, the shouldered cross members and the flooringmembers;

FIG. 6 is a view taken along line 6--6 of FIG. 5;

FIG. 6A is similar to FIG. 6 but shows one of the main rails and one ofthe cross members comprising a composite material;

FIG. 7 is a view taken along line 7--7 of FIG. 6;

FIG. 8 is a view taken along line 8--8 of FIG. 6;

FIG. 9 is a view taken along line 9--9 of FIG. 6;

FIG. 10 is a view taken along line 10--10 of FIG. 6;

FIG. 11 is a view taken along line 11--11 of FIG. 6;

FIG. 12 is a partial cross-sectional view of an alternative dual webmain rail design;

FIG. 13 is a cross-sectional view of an alternative shouldered crossmember;

FIG. 14 is a cross-sectional view of a second alternative shoulderedcross member;

FIG. 15 is a cross-sectional view of a third alternative shoulderedcross member;

FIG. 16 is a partial isometric view of the floor support of aconventional van;

FIG. 17 is a partial cross-sectional end-view of a conventional vanstructure;

FIG. 18 is a view taken along line 18--18 of FIG. 17;

FIG. 19 is a partial isometric view of the present invention floorsupport for a van;

FIG. 20 is a partial cross-sectional end-view of the present inventionfloor support van structure;

FIG. 21 is a view taken along line 21--21 of FIG. 20;

FIG. 21A is similar to the lower right-hand portion of FIG. 21 but showsone of the cross members comprising a composite material;

FIG. 22 is a partial cross-sectional end-view of another embodiment ofthe present invention that forms a portion of the floor support for avan; and

FIG. 23 is a view taken along line 23--23 of FIG. 22.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now in detail to the various figures of the drawing whereinlike reference characters refer to like parts, there is shown in FIG. 4at 120 an integrated truck bed structure. As shown more clearly in FIG.5, the structure 120 comprises two main rails 122 and 124, each having adual web 126A/126B configuration and each running parallel with alongitudinal axis 123 of the truck bed. This dual web configurationdoubles the support provided to every cross member 128 since each crossmember 128 has four points of support, indicated by reference numbers130A-130D, as opposed to only two points of support for conventionalcross members 12, as shown in FIG. 3. As such, this configurationreduces the unsupported length of the cross members 128 and permits thecross members 128 to be less heavy (e.g., the vertical height of thecross member 128 can be reduced and/or the wall thickness of the crossmember 128 can be reduced), thereby reducing the overall weight of thetruck bed.

The dual webs 126A/126B can be non-parallel (e.g., tapered) with respectto a vertical axis 127 of the main rail, as shown in FIG. 6, rather thanbeing parallel, in order to enhance the torsional strength of the mainrails 122 and 124, and reduce parallelogramming. This results in thereduction in the number of lower cross members (not shown; lower crossmembers typically comprise a "c"-channel or tube configuration and aredisposed between the main rails 10, just above the lower flanges 13 ofthe main rails 10; such lower cross members are distributed every 6-8feet along the length of the truck bed), thereby reducing the weight andassembly time of the truck bed.

Each main rail 122 and 124 may comprise, but is not limited to, acomposite material (see FIG. 6A), thereby reducing the weight of eachmain rail while maintaining its strength.

A key feature of the present invention is that each main rail 122 and124 has its top flange or surface formed by the flooring member 132,thereby greatly increasing the strength of each main rail 122 and 124.As can be seen most clearly in FIG. 5, each main rail 122 and 124 isopen at the top. When the cross members 128 are installed and theflooring member 132 put in place, the flooring member 132 itself formsthe top flange of the main rails 122 and 124. Since the strength of abeam is defined by its section modulus value, which is defined by, amongother things, the height of the beams and the areas of the web, the topflanges and the bottom flanges, the value is greatly increased when thearea of the top flange is defined by the relatively large area of theflooring member 132 as compared to the area of, for example, the topflange 11 shown in FIG. 3.

Each web 126A/126B of each main rail 122 and 124 comprises a pluralityof recesses 134 along the upper edges 136 for supporting the crossmembers 128 therein. As can be seen in FIG. 5, the recesses 134 arealigned transversely for supporting the cross members 128 therein.

As shown most clearly in FIGS. 5-11, each cross member 128 isconstructed to be non-uniform in cross-section for achieving a number ofpurposes, including optimum transference of load to the main rails122/124, reduction in length of unsupported flooring members and thelowering of floor height, thereby increasing storage space. Thefollowing is a discussion of the non-uniform cross member 128 asdepicted in FIGS. 5-11. However, it should be understood that thenon-uniform cross member 128 is exemplary only and that it is within thebroadest scope of this invention to include various designs of suchnon-uniform cross members and is not limited to those depicted in FIGS.5-11. Furthermore, it should be understood that the differentcross-sections discussed below may comprise discrete portions secured toone another or may comprise a unitary piece. The important feature isthat the various cross-sections of the cross member provide thediscussed functions. While a non-uniform cross-section is preferred, across member 128 of uniform cross-section could also be used for thevarious designs.

Each of the cross members 128 comprises a plurality of risers along theupper portion of the cross member. These risers allow the flooringmember 132 to be directly connected to the cross members 128 and mainrails 122/124, as will be discussed below (FIGS. 6, 8-9 and 11). Threeof the risers, namely risers 138,140 and 142 (hereinafter the"longitudinal risers") are aligned along the longitudinal axis 144 ofthe cross member 128 and four of the risers, namely 146-152(hereinafter, the "transverse risers") are aligned transversely of thislongitudinal axis 144. All of the longitudinal risers 138-142 havewidths that are smaller than the cross member 128, thereby creating apair of shoulders 154A/154B (FIG. 8 depicts shoulder 154B) forsupporting the ends of intermediate flooring support members 156. Theflooring member 132 is thus supported by these members 156 (whichinclude upper feet 158, see FIG. 6) in between cross members 128 (FIG.8). As a result, because these shoulders 154A/154B permit the insertionof the intermediate flooring support member 156, the unsupported length153 of the flooring member 14 (see FIG. 3) between cross members 12 canbe retained with less cross members. A "keystone"-shaped cross member128 placed on 21" centers can provide the same floor support as an"I-beam" placed on 15" centers, as indicated by reference number 160(FIG. 5). Thus, the longitudinal risers 138, 140 and 142 permit thecross members 128 to directly connect the flooring member 132, therebyeffectively making the flooring member 132 work as the top (or upper)flange of the cross member 128.

Among other things, one advantage of having the top surface of the crossmember 128 act as supporting the flooring member 132 directly is thatsuch a design reduces the floor height. For example, on most vans (asdiscussed further below), the flooring supports are carried by the topsurface of the cross members and then the flooring member is disposed ontop of those supports. If the design of the present invention is used,where the top of the cross member supports the flooring member directly,approximately 11/8-11/2 inches of extra storage space height is madeavailable. This also increases the strength of the cross members andrequires fewer of them while still retaining the same unsupported length160.

It should also be noted that the risers 138 and 142 do not extend to theextreme ends of the cross members 128 (although the risers could extendto the extreme ends); this permits the outer ends of each cross member128 to support respective "T-slots" 162 and respective anchoring members164 (e.g., a plank of wood); these items are used for securing thepayload to the truck bed but do not form any part of the patentableinvention herein.

The transverse risers 146-152 also directly carry the flooring member132 to permit the flooring member 132 to form the top flange of the mainrails 122 and 124, as discussed previously. The transverse orientationof the risers 146-152 create a pair of depressions 166 and 168 whichpermit the introduction of another "T-slot" 170 (FIG. 6) and/or anotheranchoring member (e.g., a plank of wood, not shown) to run the length ofthe truck bed. As can be seen most clearly in FIG. 5, continuousflooring support members 172 are also disposed in these depressions166/168. These continuous flooring support members 172 run the length ofthe truck bed and they also comprise upper feet 174 (FIG. 6) forsupporting the flooring member 132 (FIG. 10).

Thus, another key feature of the present invention is depicted in FIG.5: the risers 138-152 of the cross members 128 and the upper edges 136of the main rails are flush and thereby act together to provide acoplanar support surface for the flooring member 132.

For clarity in understanding the cross-sectional figures, namely FIGS.7-11, it should be noted that the flooring member 132 comprises tractionstrips 176.

To secure the flooring member 132 to the main rails, any number ofsecuring means can be used. One exemplary method (but not limited tothat method) is to use screws/bolts, as shown in FIG. 9. In particular,a bolt 178 and nut 180 can be used to secure the flooring member 132 tothe upper edge 136 of the main rails 122/124. Similarly, other bondingtechniques could be used (welding, bonding agents, etc.).

FIGS. 13-15 depict alternative cross-section designs for the crossmembers 128. As stated earlier, it is within the broadest scope of thepresent invention to include cross member designs that incorporate thefunctions of the cross member 128 described above. For example, a crossmember may include a "shoulder" function for carrying flooring membersupports while at the same time providing an upper surface forsupporting the flooring member 132 directly, thereby resulting in theflooring member 132 forming the top (or upper) flange of the crossmember 128. One exemplary means is to use a riser element (e.g., risers138-152), as described above. Similarly, other shoulder means, such asthe one depicted in FIG. 15 by the use of right-angled supports 182could be used in a cross member 228, or a unitary cross member 428 (FIG.13, a trapezoidal-shaped cross section) and cross member 328 (FIG. 14, arectangular-shaped cross section). The important function is that in allof these alternative designs, the flooring member forms the top (orupper) flange of the cross members.

To increase the stability of the cross member, the sides 186A/186B ofthe cross member 128 are non-parallel (e.g., tapered) with respect to avertical axis 184 (FIG. 8). As with the non-parallel webs of the mainrail, such tapering prevents "parallelogramming" of the cross member128. Similarly, the sides 486A/486B of the cross member 428 can betapered in the opposite direction with respect to the vertical axis 184,as shown in FIG. 13.

An alternative main rail design is depicted in FIG. 12. In thisembodiment, the dual web construction is confined to the upper portionof the main rail. To that end, the main rail 222 comprises an extrudedupper half 221 having a planar support surface 223 from which project apair of webs 226A and 226B which contain respective recesses (not shown)for receiving the cross member 128 therein. The planar support surface223 is itself supported by a pair of angled strut surfaces 225A/225B.The lower ends of these angled strut surfaces 225A/225B are formed intoa single strut 227. The single strut 227 is then coupled (e.g., weldedor bolted) to a bottom support strut 229 completing the main rail of thetrailer.

As mentioned earlier, one advantage of having the top (or upper) flangeof each cross member 128 formed by the flooring surface 132 is that sucha design reduces the floor height. In trucks without main rails, such asvans, refrigerated vans, container chassis or any box-type truckstructures, the integrated floor and cross member design reduces theheight of the floor and cross members, resulting in more interior spacewhile increasing both the trailer structural strength and the crossmember strength. It also reduces the number of cross member required,therefore reducing weight and assembly time. The following discussionconcerns a van structure, although it should be understood that this isby way of example only, and not limitation, and that vans, refrigeratedvans, container chassis or any box-type truck structure is also coveredby the following discussion.

FIGS. 16-18 depict the conventional van structure (e.g., U.S. Pat. No.3,692,349 (Ehrlich)) whereby no main rails are used but only crossmembers 12. In particular, the cross members 12 are typically "I-beams"and whose upper flange 17 supports the feet 16 of the flooring member 14(e.g., aluminum orwood). The cross members 12 are secured to the sidesof the van by rivets 19 that secure each cross member mounting plate 21to a lower corner extrusion 25. The upper portion of the extrusion 25comprises a U-shaped member 27 that contains the outer skin 29 of thevan as well as a side support 31. Rivets 19 also secure all thesemembers together. A projecting flange 33 on the inside surface of theU-shaped member 27 permits the flooring member 14 ends to be insertedthereunder, thereby forming a loose floor connection. The flooringmember 14 can then be further secured to the top flange of the crossmember 12 with rivets 19 (or bolts or screws), as shown in FIG. 18. Theroof 35 of the van is formed by a roof skin 37 that is supported by aroof support 41. The ends of the roof skin 37 and the roof support 41are secured inside upper corner extrusions (only one 43 of which isshown), similar to the lower corner extrusion 25; rivets 19 are alsoused.

In contradistinction, with the present invention cross member 128installed (FIGS. 19-21) in the van, the flooring height can be reduced,the reduction in flooring height being depicted by the reference number500 in FIG. 21, while maintaining the same size (501) cross member 128.This reduction in height can be directly observed by overlaying FIG. 21(present invention) on top of FIG. 18 (prior art). Thus, the presentinvention permits the same size (the vertical dimension of the crossmembers shown in FIG. 18 and FIG. 21) cross member and the same sizeflooring (reference number 14 in FIG. 18 and reference number 132 inFIG. 21) to be used while lowering the floor height, thereby providingmore storage space in the van, and while strengthening the vanstructure. This added strength to the van structure occurs because theentire flooring member 132 acts as the top (or upper) flange of thecross members 128 (FIGS. 19-21). In contradistinction, since theflooring member 14 (FIG. 17) of a conventional van is simply resting ontop of the cross members 12, the flooring member 14 provides no addedstrength to the cross member 14 and to the overall van structure.Typically, the box-like structure of the van can be considered like an"I-beam" whereby the top roof supports acts as the top flange of the"I-beam", the sidewalls of the van act as the web of the "I-beam" andthe cross member acts as the bottom flange. However, with the presentinvention installed, the entire flooring member 132 and the crossmembers 128 act as the lower flange of this "I-beam", thereby greatlyincreasing the strength of the van structure. Because the design of thepresent invention increases the strength of the van structure, lesscross members need to be used, thereby reducing the weight of the van.

In particular, as shown in FIG. 19, the cross member 128 of the presentinvention is shown with the intermediate floor support member 156 on afront shoulder 154. Thus, as with the cross member design discussedearlier with respect to the truckbed, the flooring member 132 forms thetop (or upper) flange of the cross member 128 and, thereby, thisshouldered cross member 132 has all of the strength advantages discussedpreviously while at the same time lowering the floor height to providemore storage space in the van.

The cross member 128 in the van is secured to the lower corner extrusion25 by a cross member mounting plate 521 by rivets 19. In addition,rather than forming a loose floor connection at the sides of theflooring member as in the conventional van, the flooring member 132comprises vertical flanges 523 that are fixedly secured to the U-shapedmember 27 of the lower corner extrusion 25 via rivets 19; this forms adirect connection of the flooring member 132 to one side of the U-shapedmember 27. Alternatively, although not shown, it is also within thebroadest scope of the present invention to have the vertical flanges 523be integral with the U-shaped member 27, rather than having the flanges523 riveted to the U-shaped members 27; thus, a one piece member is thusformed between the flooring member 132 and the U-shaped member 27.Furthermore, as shown in FIG. 20, rivets 19A are shown which secure theflooring member 132 to the intermediate flooring support member 156.

Attempting to provide more storage space in the van may be accomplishedby simply reducing the combination height of the flooring member 14 andcross member 12 i.e., reducing the vertical dimension of these twocomponents since the flooring member 14 rests on top of the crossmembers 12. However, doing so sacrifices the strength of the flooringstructure (as well as the overall van structure). In contradistinction,with the unitized flooring member 132/cross member 128 design of thepresent invention installed, the same size cross member 128 and flooringmember 132 may be used, i.e., there is no need to reduce the size ofthese components.

FIGS. 22-23 depict an alternative cross member design for a vanstructure (or any of the other container truck structures) which iswithin the scope of the present invention that does not require the sizeof the cross member to be reduced. This alternative cross member isshown at 528 in FIG. 23. In particular, the cross member 528 has an"I-shaped" cross section but has integral shoulder members on each sideof its top portion, indicated by 554A and 554B. As can be appreciated bythose skilled in the art, this modified top portion of cross member 528also permits the lowering of the floor height while maintaining the samesize cross member (and, therefore, the same strength), i.e., the height501 of the cross member 528 is the same as for cross member 128. Theforward shoulder 554A and rear shoulder 554B support intermediateflooring support members 156 which in turn support the flooring member132. As with the other cross member embodiments discussed above, theflooring member 132 thus also forms the top (or upper) flange of thecross member 528.

Although one of the advantages of the present invention is that there isno need to reduce the size 501 of the cross members or the flooringmembers to achieve the increase in storage space, the size 501 of thecross member 128, or cross member 528, can be reduced; this is becausethe unitized design permits the entire flooring member 132 to act as thetop flange of the cross members 128, thereby greatly increasing thestrength of the payload support structure. Thus, by decreasing the sizeof the cross member 128, the van can be made even lighter whilemaintaining its payload support capacity.

It should be noted that the cross members 128 of the van may have any ofthe cross sectional shapes depicted in FIGS. 7-15 with regard to theflatbed trailer.

It should be further noted that the main rails, both the intermediateflooring support members and the continuous flooring support members,and the cross members (all embodiments) may be constructed of composite(see FIGS. 6A and 21A); however, the flooring members 132 are preferablyconstructed of aluminum for providing better stiffness and becausealuminum provides for better shock resistance.

Without further elaboration, the foregoing will so fully illustrate myinvention that others may, by applying current or future knowledge,readily adopt the same for use under various conditions of service.

I claim:
 1. A flatbed trailer apparatus having a longitudinal axis, saidapparatus comprising:at least two main rails oriented parallel to thelongitudinal axis of said apparatus and a plurality of cross memberscoupled to said at least two main rails; each of said plurality of crossmembers comprising shoulder portions; intermediate flooring supportmembers disposed in between said plurality of cross members and havingends supported by said shoulder portions; and continuous flooringmembers disposed on top of said intermediate flooring support members.2. The flatbed trailer apparatus of claim 1 wherein each of saidplurality of cross members comprises a keystone-shaped cross section toform said shoulder portions.
 3. The flatbed trailer apparatus of claim 1wherein each of said plurality of cross members comprises atrapezoidal-shaped cross section to form said shoulder portions.
 4. Theflatbed trailer apparatus of claim 1 wherein each of said plurality ofcross member comprises a rectangular-shaped cross section to form saidshoulder portions.
 5. The flatbed trailer apparatus of claim 1 whereineach of said plurality of cross members comprises sides orientedtransversely to the longitudinal axis of said apparatus and wherein saidshoulder portions are formed of right-angled members secured on eachside of said cross members.
 6. The flatbed trailer apparatus of claim 1wherein said at least two main rails comprise composite material.
 7. Theflatbed trailer apparatus of claim 1 wherein each of said plurality ofcross members comprises composite material.
 8. The flatbed trailerapparatus of claim 1 wherein each of said at least two main rails isformed of at least two substantially vertical and adjacent webs that areinterconnected at their lower ends.
 9. The flatbed trailer apparatus ofclaim 1 being unitized wherein each of said at least two main railscomprises upper ends formed to receive a portion of said plurality ofcross members such that a top surface of each of said plurality of crossmembers and a top surface of said upper ends are substantially coplanarwhen said plurality of cross members are coupled to said at least twomain rails, and wherein said continuous flooring members are disposed ontop of said upper ends and on top of said plurality of cross members,said continuous flooring members being secured to said upper ends toform an upper flange of each of said at least two main rails to unitizesaid continuous flooring members with said at least two main rails.